Thermostatic switch



J as

proceeds and which involve the provision o Patented Mar. 5, 1929.

UNITED STATES lflt isltfi PATENT CARL T. PENTON, OF BUFFALO, NEW 'YGIRK.

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Application filed December 6, 1923. Serial No. 878,840.

This invention relates to improvements in thermostatic switches,proposing a switch which is available for the automatic control,according to temperature variations, of electrical appliances orapparatus, such as ovens, water heaters and the like, where it isdesirable that the temperature be maintained at a certain approximatedegree or within a certain range.

The principal objects of the invention are to secure a quick make andbreak of the cooperating electric contacts whereby destructive arcing iseliminated and to provide for this purpose mechanism of simplestructural character which will be at all times certain and reliable andwill not be liable to derangement.

A further object is to promote facility in the fitting and removal ofthe operating parts relatively to the structure with which thethermostat is associated by providing for the assembly of such parts asa self contained unit through which the circuit to be controlled iscompleted.

' A further object is to provide facility in regulating the degree oftemperature at which the circuit will be opened and below which it willbe closed.

With the above objects in View the invention consists generally incertain novel features of structure and combination which will bepointed out in detail as the description friction means for retardingthe action of the thermostatic spring, provision for the removablemounting of the operating parts as a self contained conducting unit, andprovision for the regulation of the critical temperature degree or rangeby the movement of an indicating part and without the necessity of anymanipulation or adjustment of the co-opersting contacts.

An embodiment of the invention is illustrated in the accompanyingdrawing wherein: I Figure 1 is a longitudinal sectional view of theswitch.

' Figure 2 is a front elevation thereof.

Figures 3 and 4 are sectional views on the lines 33 and 44 of Figure 1.

Figure 5 is a sectional view on the line 5-5 of Figure 3.

Figure 6 is a sectional view on the line 6-6 .df Figure 1.

The switch is supportedby the wall A of the electrical appliance to becontrolled, such for example as a water heater,'and is subject to theheat developed within the chamber of such appliance. The casing in whichthe operating mechanism is enclosed is preferably made in two parts,namely the casing proper as 1 and a sleeve-like extension theremade asseparate parts, the casing having a collar 3 projecting from its rearwall and fill? ting over the front end of the extension upon 1 which itis secured by a screw 4. In order to prov de access to the operatingparts the front wall 5 oi the casing is removably secured, as by screwsc, to the body of the cas-,

ing.

The support for the operating parts consists of a metallic frame Z whichis secured by fastening bolts 8 and i) to the rear wall or the casing 1.The bolts 8 and '9 are provided on their projecting rear ends withsecuring nuts 10 and are available as binding posts for the connectionor the terminals 12 of the wires which are joined to the terminals ofthe heating element or other electrical receiving device. The frame 7 isinsulated from the casing 1 by a plate 13 of suitable insulatingmaterial which is fitted between said frame and the rear wall of saidcasing and is supported by contact with the frame 7 and is insulatedfrom the casing 1; the bolt 9 is insulated both from the frame and fromthe casing.

Any suitable make-and-break device may be employed, that shown beingpreferred and consisting of a laterally arranged stationary contact 14connected to the bolt 9 and cooperating with a contact 15 provided on amovable bar 1-6. The frame "l is provided along its upper side with apair of spaced lugs l? and i8 whereof the 11'' carries the contact let(from which it is suitably insulated) and the lug '18 serves "for theattachment, as bye screw 19, of an indicating scale 20 which bridgessaid lugs and cooperates with an indicating linger 211, the scale 20 andfinger 21 being visible through a window 22 in the front wall 5. t

The bar 16 is operated by a thermostatic spring 23, as shown ahelical ywound spring, and projects radiall from a head 24 mounted fast at oneend or a longitudinal sleeve 25 which functions as a shaft and ismounted f the bolts 8 and 9. The belt 8 is in electrical lit) upon alongitudinal bar 26. The bar 26 is supported for turning adjustment withreference to its axial center in a thimble 27 provided at the lower side.of the frame 7 and, together with the sleeve 25, projects into theextension 2. The bar 26 is provided at its rear end with a head 28 andthe sprin 23 which is located in the extension 2 beyon the sleeve 25 issecured at its ends to said sleeve and said head. The bar 26 is heldagainst displacement under the pressure of the spring 23 by a nut 29which is fitted at the front end .of the bar upon a threaded portion 30and is backed by a suitable cushioning washer 31, in turn backed by thethimble 27.

The thimble 27 also provides a bearing for an adjusting disc 32 which ismounted behind said thimble upon the bar-26 to which it is made fast inany suitable manner and which carries the finger 21. The disc 32 ispressed against the rear face of the thimble 27 by the head 24 (underthe pressure of the spring 23) and may be turned by the finger 21 ineither direction to eflect a corresponding movement of the rod 26 and aconsequent regulation of the tension of the spring 23. A friction disc33, preferabl composed of vulcanized fiber is fitted on t 1e rod 26between the head 24 and the disc 32, the friction disc being backed bythe adjusting disc and having a flat and wide contact with the adjacentface of the head 24 which is pressed against the friction disc by thespring 23.

The extension 2 is preferably closed at its rear end by a head 34 andthe spring 23 is ar-' ranged in the portion of the extension whichprojects into the chamber provided by the wall A. where it is sensitivelresponsive to temperature variations in sai chamber. Below a determineddegree or range of temperature the spring'23, acting on the sleeve 25,and through it on the bar 16 will cause the contact 15 to engage thestationary contact 14. Above such degree or range of temperature the sring 23 similarly causes the contact 15 to disengage the contact 14. Thedegree or range of temperature to be maintained is determined by theposition of the finger 21 with reference to the scale 20, the movementof said finger along said scale being'effestive, through the rod 26. toregulate the tension of the spring whereby if the tension be decreasedthe spring will disengage the contacts 15 and 14'at a lower temperatureand if the tension be increased the spring will disengage such contactsat a higher temperature. The finger 21 is adjusted manually glong thescale 20, the cover 5 first being removed as is obvious.

The movement of the bar 16 to effect the engagement or disengagement ofthe contact 15 relatively to the contact 14 is quick and in the natureof a snap action whereby destructive arcing, which might otherwise bedue to the high tension currents employed, is

V cor-operating avoided. This snap action of the bar 16 is secured bythe provision of the friction disc 33 which, engaging the head 24, actsas a brake .on the sleeve 25 in opposition to the spring 23. It followsthat before the spring 23 can produce a movement of the bar '16 itmust'store suflieient power to overcome the braking effect of the disc33 with the result that the bar 16 can have no gradual movement but ismoved quickly or snapped in either direction accordingly as it is beingoperated to engage or disengage the contacts 15 and 14.

The operating parts are assembled to constitute a selfcontained'conducting unit which may be removed from and inserted intothe casing 1 and its extension 2. The circuit of the heating element orother electrical receiving device is closed through the terminal 9,contacts 14 and 15, bar 16, sleeve 25, rod 26, disc 32, frame 7 andterminal 8. The frame 7 is the support for thevoperating unit and suchunit is removed by first removing the front Wall 5 of the casing 1 andthen disconnecting the bolts 8 and 9. If dcsiredthe casing 1 and theoperating unit may be removed together from the extension 2 after firstbacking off the screw 4.

Having fully described my invention, I

claim:

an indicating scale and co-operating finger constituting companionrelatively movable elements, and operative connections between one ofsaid elements and said rod whereby a.

movement of said element relatively to its companion element effects anadjustment of said rod.

2. In a thermostatic switch, the combination of a movable contact part,a thermostatic spring for operating the same, means including anadjustable rod for regulating the tension of said s ring, an indicatingscale and nger constituting companion relatively movable elements,operative connections between one of said elements and said rod wherebya movement of said element relatively toits companion element efi'ectsan adjustment of said rod, and means acting with braking effect tooppose the action of said spring whereby the latter must store power toa certain degree in order to operate said contact part.

3. In a thermostatic switch, the combination of a supporting partprovided with a thimble, a rod mounted in and projecting from saidthimble, a sleeve mounted on and supported by said rod, a thermostaticspring connected at its ends to said rod and sleeve, the rod beingadjustable whereby to regulate the tension of said spring, and a movablecontact part actuated by said sleeve.

4. In a thermostatic switch, the combination of a supporting partprovided with a thimble, a rod mounted in and projecting from saidthimble, a sleeve mounted on and supported by said rod, a thermostaticspring connected at its ends to said rod and sleeve, a movable contactpart actuated by said sleeve, and means acting with braking effect tooppose the action of said spring whereby the latter must store power toa certain degree in order to operate said contact part.

5. In a thermostatic switch, the combination of a supporting partprovided with a thimble, a rod mounted in and projecting from saidthimble, a sleeve mounted on and supported by said rod, a thermostaticspring connected at its ends to said rod and sleeve, the rod beingcapable of adjustable movement, an indicating finger connected to saidrod for adjustably moving the same, a scale with which said fingerco-operates, and a movable contact part actuated by said sleeve.

6. In a thermostatic switch, the combination of a supporting partprovided with a thimble, a rod mounted in and projecting from saidthinible, a sleeve mounted on and supported by said rod and providedwith a head, a movable contact part operated by said sleeve, athermostatic spring connected atv its ends to said rod and sleeve, and afriction disc fitted upon said rod and pressed against said head withbraking effect.

7. In a thermostatic switch, the combination of a supporting partprovided with a thimble, a rod mounted in and projecting from saidthimble, a sleeve mounted on and supported by said rod, a thermostaticspring connected at its ends to said rod and sleeve, the rod beingcapable of adjustable movement, a finger connected to said rod and bywhich said rod may be adjusted, said sleeve being provided with a head,a friction disc fitted upon said rod, and engaging said head withbraking effect, and a movable contact part actuated by said sleeve.

8. In a thermostatic switch, the combination of a movablecontact part, athermostatic spring for operating the same, means for regulating thetension of said spring, and a frictional connection between said movablecontact part and a relatively stationary part, said connection actingwith braking effect to oppose the action of said spring whereby thelatter must store power to a certain degree in order to operate saidcontactpart.

9. In a thermostatic switch, the combination of a movable contact part,a thermostatic spring for operating the same, an indicating scale havinga movable element, means actuated by said element for regulating thetension of said spring, and means acting with braking effect to opposethe action of said spring whereby the latter must store power to acertain degree in order to operate said contact part.

In testimony whereof I atfix my signature.

CARL T. PEN TON

